DURABILITY OF A LOW CEMENT CONTENT MIX

In this investigation, compressive strength, permeability and resistance to alternate freezing and thawing cycles were measured and compared for a plastized, air-entrained, low cement content mix, and a 1:2:4 control mix. Air content, plastic density, and slump were also measured. Additional tests were carried out on 21 MN/m squared mix with excess water added, and without admixture. The actual mix designs are detailed. The test results on plastic and hardened concrete indicate that the more economical, plasticized air entrained concrete has greater durability than the control 1:2:4 mix and in normal circumstances would serve the client better. For entrained air to be effective in increasing durability, it is necessary for certain parameters such as bubble size, spacing and uniformity to be observed. Previous studies suggest that for similar mix proportions, 70% of the air bubbles will have a diameter between 0.05 and 1.2 mm with an average spacing of about 0.25 mm. This investigation has shown that the durability of concrete with cement content as low as 2000 kg/m cubed can be made greater than 1:2:4 nominal mix by the addition of 4-5% entrained air, together with a reduction in the water/cement ratio by the use of a water reducing agent, and that the cohesion and finish is greatly improved. The use of such an admixture enables considerable savings to be made on mix costs.

  • Availability:
  • Corporate Authors:

    Cement and Concrete Association

    Wexham Spring
    Slough SL3 6PL, Buckinghamshire,   England 
  • Authors:
    • Oldham, P C
    • Sheriff, A N
  • Publication Date: 1978-7

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 19-21
  • Serial:
    • CONCRETE
    • Volume: 12
    • Issue Number: 7
    • Publisher: THE CONCRETE SOCIETY
    • ISSN: 0010-5317

Subject/Index Terms

Filing Info

  • Accession Number: 00184612
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Feb 3 1979 12:00AM